Current Anesthesiology Reports (2019) 9:257–262 https://doi.org/10.1007/s40140-019-00338-9

REGIONAL ANESTHESIA (P KUKREJA, SECTION EDITOR)

Quadratus Lumborum Block: a Technical Review

Avni Gupta1 & Rakesh Sondekoppam2 & Hari Kalagara3

Published online: 22 June 2019 # The Author(s) 2019, corrected publication November 2019

Abstract Purpose of Review Ultrasound-guided quadratus lumborum block (QLB) is gaining popularity in regional anesthesia for various surgical procedures. The purpose of this review is to understand the relevant clinical anatomy, different mechanisms of actions, and techniques used for the block and clinical evidence so far. Recent Findings The current data suggests a wide dermatomal distribution of the local anesthetic from T7-L2. The evidence regarding its utility is still evolving but has shown reduced opioid requirements for cesarean sections, lower abdominal surgery, and hip surgery. Prolonged analgesia has been reported as compared with more conventional transversus abdominis plane (TAP) block. This block has also been reported for above knee amputation, femoral-pop bypass, lumbar laminectomy and fusion, bone graft, and iliac and acetabulum fracture. Summary Quadratus lumborum can be performed through different approaches which requires sound knowledge of anatomy. Further research to determine which approach yields best results is warranted.

Keywords Quadratus lumborum block . Ultrasound . Regional anesthesia . Cesarean section . Abdominal procedures . Hip surgery

Introduction blockade [7–9]. Further research regarding the best technique to do this block is warranted. Quadratus lumborum block (QLB) under ultrasound has been one of the interfascial plane blocks being popularized in re- gional anesthesia over the last few years given the vast number of indications in a variety of abdomino-pelvic surgeries in Anatomical Considerations pediatrics and adults. In clinical studies, it also has been shown to have opioid sparing effects [1–5] and prolonged Quadratus lumborum muscle (QLM) is an axial muscle situ- post-operative analgesia than more conventional procedures ated in the deep posterior mainly intended to like TAP blocks [6••]. The current review focuses on the an- stabilize the spine and also acts as an accessory muscle of atomical considerations, different approaches, and a review of inspiration. Its function is to stabilize the thorax during respi- the safety and clinical efficacy of this block. Differences in ration and hence has its origin from the inner lip of the technique may result in a differential spread of local anesthetic posteriomedial iliac crest and inserts into the transverse pro- leading to variation in sensory and motor dermatomal cess of L1-4 as well as medial border of the 12th rib. Psoas major lies anterior to quadratus lumborum on either side of the vertebral body. Posterior to quadratus lumborum lies the This article is part of the Topical Collection on Regional Anesthesia group of muscles called erector spinae consisting of * Hari Kalagara multifidus, longissimus, and iliocostalis. Lateral and posterior [email protected] to quadratus lumborum lies the anterior abdominal wall mus- cle group, namely, transversus abdominis, internal oblique, 1 Millennium Pain Center, Unity Point Health-Methodist Hospital, and external oblique from anterior to posterior (Fig. 1). Peoria, IL, USA Lateral and anterior to quadratus lumborum lay the retroperi- 2 University of Alberta Hospital, Edmonton, Alberta, Canada toneal structures like the , paranephric fat, posterior 3 Department of Anesthesiology, The University of Alabama at renal , and anterior thoracolumbar fascia/transversalis Birmingham (UAB), Birmingham, AL, USA fascia. Both quadratus lumborum and psoas muscle lie 258 Curr Anesthesiol Rep (2019) 9:257–262

thereby allowing a continuity with the over the ventral aspect of the quadratus lumborum. This may be a potential path of local anesthetic spread from QLB to the lumbar plexus.

Neurovasculature

The iliohypogastric, ilioinguinal, and subcostal nerves lay on the ventral aspect of quadratus lumborum muscle and are encased within the transversalis fascia [13]. The consistent level of sensory dermatomal level achieved through quadratus lumborum block involves T12-L2 with various techniques [14–21]. This explains the consistent blockade of these three nerves since these nerves travel over the QLM and are directly related to the muscle [7, 9•, 14–22]. The lateral femoral cuta- Fig. 1 Cross-section of the posterior abdominal wall at L4 vertebral level neous nerve, obturator, and femoral nerve lie within the psoas showing the relationship of quadratus lumborum muscle (QLM) to the muscle at L4 or L5 vertebral level and exit the muscle more transverse process (TP), erector spinae group of muscles (ESM), and the caudally [23, 24]. The data does not show consistent blockade latissimus dorsi muscle (LD). Spinal cord (SC) is also shown along with of these nerves but there is a potential for the spread as the three abdominal muscles: the transversus abdominis (TA), internal oblique (IO), and external oblique (EO) muscles. The various discussed above. Posterior to quadratus lumborum are the approaches to QLB [lateral QLB (LQL), anterior/transmuscular QLB dorsal rami of spinal nerves innervating the erector spinae (TQL), and posterior QLB (PQL)] are shown in dashed arrows along muscles. Sympathetic nerve fibers innervating abdominal with transversus abdominis plane block (TAP) and the transversalis muscles are also located posterior to quadratus lumborum fascia plane block (TFP). Courtesy Prof. R.D. Hersch, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland. Picture from and innervate thoracolumbar fascia [25]. This could be one the former Visible Human Web Server of the reasons for analgesia provided through the posterior approach of quadratus lumborum block [26]. Lumbar arteries posterior to the lateral and medial arcuate ligament of the travel in close proximity and sometimes within the substance diaphragm respectively. of the QLM. They may be a source of bleeding following the Quadratus lumborum is surrounded by thoracolumbar fas- block and we recommend color doppler query in the path of cia. Posterior thoracolumbar fascia surrounds the erector needle trajectory before performing the block. spinae muscle. Middle thoracolumbar fascia lies between the erector spinae and quadratus lumborum, whereas the anterior layer lies anterior to quadratus lumborum and psoas major Technical Considerations [10]. Anterior thoracolumbar fascia is continuous with the transversalis fascia, the deep fascia of the in a two- Although there is some controversy regarding nomenclature layer model. The anatomy of the anterior thoracolumbar of different approaches to perform the block, the most popular fascia/transversalis fascia is unique and may be crucial to consensus is to name on the basis of anatomical location of our understanding of the pattern of spread following injections needle tip in relation to quadratus lumborum muscle [27••]. ventral to the QLM. Transversalis fascia divides into two Hence, the three different approaches that can be easily re- layers: the inner layer is continuous with endothoracic fascia membered are with respect to the QLM itself which are the in the thorax and the outer layer blends with the arcuate liga- lateral, posterior, and anterior quadratus lumborum block. ments of the diaphragm. Endothoracic fascia provides a po- Standard safety and aseptic measures prior to performing tential pathway for cephalad spread of local anesthetic from for all regional blocks should be followed. The patient can be the abdomen to the thoracic paravertebral space [7, 11, 12]. positioned in prone, lateral, or sitting position depending on While there is a channel for the injectate deposited on the patient and physician preferences. We recommend in-plane ventral aspect of the QLM to reach the thoracic paravertebral ultrasound approach with direct needle visualization along space, whether this is clinically relevant needs further studies. with hydro dissection using a low-frequency curvilinear probe Another important anatomical consideration is that the psoas given that it is a deeper block. Typical needle length used is major muscle lies in close proximity to QLM and is ventro- 80–150 mm depending on body habitus of the patient. The medially located. The while housing the block can be done as a single shot injection as well as a con- lumbo-sacral plexus may be commonly split by a fascial layer tinuous catheter infusion, which determines gauge of the nee- between the posterior 1/3 and anterior 2/3 of the muscle dle. The most common local anesthetics used are 0.2–0.5% Curr Anesthesiol Rep (2019) 9:257–262 259

Fig. 2 Lateral QLB without (a) and with (b) highlighting. QL, quadratus lumborum muscle; TA, transversus abdominis tapering into transversalis fascia at the lateral border of QL; IO, internal oblique muscle; EO, external oblique muscle. The needle is shown in yellow arrow

ropivacaine [2•, 3] or 0.1–0.25% bupivacaine [1, 5••, 6••]. muscle between quadratus lumborum and psoas major (Fig. Due to large volumes injected, special attention should be 4). Alternatively, a subcostal oblique approach has been de- made regarding toxic threshold of local anesthetic selected scribed in which the probe is placed in the parasagittal plane for blockade. Typical volume used ranges from 0.2–0.5 ml/ tilted medially at the level of the 12th rib approximately 4– kg (ref) on each side [1–6]. 6 cm from the midline [8]. The needle is introduced caudal to The figure demonstrates different approaches of block in the transducer probe, in-plane in a caudal to cranial trajectory relation to anatomy (Fig. 1). There is insufficient evidence with the final position as mentioned above (Fig. 5). The spread recommending one approach over the other for specific surgi- has been along the anterior thoracolumbar fascia through the cal indications. endothoracic fascia into the thoracic paravertebral space in For lateral quadratus lumborum block (Fig. 2), the needle is addition to blocking the lumbar nerve roots [7, 9•, 22]. positioned lateral to the ultrasound probe in the anterior to posterior trajectory. The needle further penetrates the anterior abdominal wall muscle group (external oblique, internal Indications and Clinical Evidence oblique, and transversus abdominis). The final position of the needle is lateral to quadratus lumborum. The injectate Based on the current randomized trials and case reports, spreads to transversus abdominis muscle plane and subcuta- quadratus lumborum blocks have been used for multiple sur- neous area [28•], although clinically, a more extensive distri- geries, including cesarean section [1, 2, 3••, 6••] and gyneco- bution has been reported [2–4]. logical [31] and lower abdominal surgeries [5••, 32]. It has The needle trajectory can be anterior-posterior or posterior- also been used for analgesia for colostomy closure [16], hernia anterior for posterior quadratus lumborum block. The final repairs [33, 34], gastrectomy [35], and nephrectomy [17, position of the needle tip is between erector spinae and 36–39]. It has been used for various lower limb surgeries like quadratus lumborum muscle on the posterior surface of hip arthroplasty [4, 14, 18, 20, 40–42], above knee amputation quadratus lumborum muscle (Fig. 3). This approach demon- in combination with sciatic block [43], iliac crest bone graft, strates the spread along middle thoracolumbar fascia [9•, 28•]. and iliac and acetabulum fracture [44]. It has been used in Similar to the posterior quadratus lumborum, the anterior conjunction with lumbar plexus block and sciatic nerve blocks quadratus lumborum can have either an anterior-posterior or for femoral-popliteal bypass [45]. There has been a case report posterior-anterior needle trajectory [29••, 30] with the final regarding the utilization of this block of lumbar laminectomy position of the needle tip anterior to the quadratus lumborum and fusion [46]. The use of posterior quadratus lumborum

Fig. 3 Posterior QLB. QL, quadratus lumborum muscle; EO, external Fig. 4 Anterior QLB. TP, transverse process; VB, vertebral body; QL, oblique muscle; IO, internal oblique muscle; TA, transversus abdominis quadratus lumborum muscle; ESM, erector spinae muscle; PMM, psoas muscle; red arrow, needle path for posterior QLB major muscle; red arrow, needle path for anterior QLB 260 Curr Anesthesiol Rep (2019) 9:257–262

to the nerve roots or branches of lumbar plexus through spread in paravertebral spaces or via transversalis fascia is likely re- sponsible for weakness of hip flexors (psoas and iliacus) and knee extensors (quadriceps). Quadriceps weakness was re- ported to be most commonly associated with anterior quadratus lumborum block, followed by posterior and lateral approaches respectively [47]. There is insufficient data on the recommended approach of the block as well as concentration or volume of local anesthetic to be used to avoid this Fig. 5 Subcostal QLB. Rib, 12th rib; ESM, erector spinae muscle; QL, complication. quadratus lumborum muscle; PMM, psoas major muscle; MTLF, middle Hypotension has been reported and is possibly related to thoracolumbar fascia; ATLF, anterior thoracolumbar fascia; red arrow, needle path for anterior subcostal QLB spread of local anesthetic in the paravertebral spaces [35]. Other considerations should be local anesthetic toxicity due to large volume used specially in cases of bilateral block for breast reconstruction using transverse rectus blocks [49]. abdominis flaps has also been reported [15]. The complications related to technical challenges of the Posterior quadratus lumborum block has been shown to deeper block and inadequate visualization and hence injury reduce morphine requirements for 48 h as compared with to surrounding structures should be kept in mind. Injury to placebo and TAP block after cesarean sections in two pleura, kidney, retroperitoneal hematoma, and nerve roots randomized control trials [1, 6••]. Two further randomized are potential complications. Full aseptic precautions should control trials using lateral quadratus lumborum block also be used to avoid infection or abscess formation. showed reduced opiate consumption after cesarean sec- tions [2•, 3]. Lateral quadratus lumborum block has been shown to reduce Visual Analogue Scale (VAS) pain score and 24-h opioid consumption as compared with femoral Caveats nerve block for hip hemiarthroplasty for femoral nerve fracture in another randomized control trial [4]. Reduced & Interfascial blocks have variability in injectate spread. Numeric Rating Scale (NRS) pain scores have been This is also true for QLB as evident from both clinical shown in laparoscopic gynecological surgery with poste- and anatomical studies. Thus, an injectate following rior quadratus lumborum block [30]. A randomized con- QLB definitely covers the T12-L1 nerves as they travel trol trial done in the pediatric age group for inguinal her- in direct relation to the muscle itself but depending on the nia surgery/orchiopexy showed reduced rescue analgesia surrounding anatomy and injectate pressure, it can spread requirements using posterior quadratus lumborum block cephalad to the lower thoracic paravertebral space, later- as compared with TAP block [5••]. Transmuscular ally into the TAP plane, anteriorly into the psoas major quadratus lumborum block used in patients undergoing muscle, and thus to the lumbar plexus. total hip arthroplasty showed reduction in length of stay & Anatomical studies and case reports are only hypothesis and intraoperative opioid use [42]. generating and should not be taken as clinical evidence. Hence, clinical decision-making should not be based on their findings. Contraindications & There is still a need for better evidence with regard to the best approach and the utility of the technique itself in the Allergy to local anesthetics, local site infection, sepsis, bleed- form of multicenter randomized controlled trials (RCT) ing disorder, and anticoagulation are absolute contraindica- and in comparison with the current gold standard tech- tions for the procedure since it is a deep block. Relative con- niques such as thoracic epidurals for abdominal surgeries traindications include known neurological disorder, anatomic and probably peripheral nerve blocks for lower extremity abnormalities, and hemodynamically unstable patient. surgeries. & QLB are deep blocks and hence may offset the presumed safety advantages of other interfascial plane blocks such Complications as TAP blocks and blocks. We are still unfa- miliar with the clinical presentation of hematological com- Lower extremity weakness has been reported with quadratus plications and based on the limited evidence, it seems that lumborum block leading to delay in mobilization and the hematological complications may have a delayed and prolonged hospital stay [47, 48].Localanestheticdistribution atypical presentation. Curr Anesthesiol Rep (2019) 9:257–262 261

Conclusions ropivacaine in postoperative analgesia after a cesarean section: a controlled clinical study. Ginekol Pol. 2018;89:89–96. 4. Parras T, Blanco R. Randomised trial comparing the transversus There is upcoming clinical evidence that quadratus lumborum abdominis plane block posterior approach or quadratus lumborum block can provide perioperative analgesia for various lower block type I with femoral block for postoperative analgesia in fem- abdominal, pelvic, and hip surgeries due to a consistent der- oral neck fracture, both ultrasound-guided. Rev Esp Anestesiol – matomal coverage of the surgical site. While it has also been Reanim. 2016;63:141 8. 5.•• Oksüz G, Bilal B, Gürkan Y, Urfalioğlu A, Arslan M, GişiG,etal. used for upper abdominal, renal, and vascular surgeries, fur- Quadratus lumborum block versus transversus abdominis plane ther evidence is warranted. Different approaches have been block in children undergoing low abdominal surgery: a randomized described to perform the block requiring a sound knowledge controlled trial. Reg Anesth Pain Med. 2017;42:674–9 of anatomy and technical expertise of ultrasound. The data, Prospective, double-blind, randomized study in pediatric pa- tients undergoing unilateral repair or although limited to few studies, shows prolonged analgesia, orchiopexy. Quadratus lumborum block provided superior reduced hospital stay, and reduced opioid requirements for and prolonged analgesia compared to Transversus abdominis abdominal surgeries, cesarean section, and hip surgery. plane block. 6.•• Blanco R, Ansari T, Riad W, Shetty N. Quadratus lumborum block Compliance with Ethical Standards versus transversus abdominis plane block for postoperative pain after cesarean delivery: a randomized controlled trial. Reg Anesth Pain Med. 2016;41:757–62 A RCT trial comparing the Conflict of Interest Avni Gupta, Rakesh Sondekoppam, and Hari quadratus lumborum block versus Transversus abdominis Kalagara declare they have no conflict of interest. plane block for postoperative pain after cesarean delivery. This study showed the benefits of QL block over TAP block Human and Animal Rights and Informed Consent This article does not in reducing the morphine consumption up to 48 hours contain any studies with human or animal subjects performed by any of postoperatively. the authors. 7. Dam M, Moriggl B, Hansen CK, Hoermann R, Bendtsen TF, Børglum J. The pathway of injectate spread with the transmuscular Open Access This article is licensed under a Creative Commons Attri- quadratus lumborum block: a cadaver study. Anesth Analg. – bution 4.0 International License (https://creativecommons.org/licenses/ 2017;125:303 12. by/4.0/), which permits use, sharing, adaptation, distribution and repro- 8. Elsharkawy, H, Ahuja, S, DeGrande, S, Maheshwari, K, Chan, V duction in any medium or format, as long as you give appropriate credit (2019) Subcostal approach to anterior quadratus lumborum block to the original author(s) and the source, provide a link to the Creative for pain control following open urological procedures. J. Anesth. Commons licence, and indicate if changes were made. The images or (2019) 33:148. other third party material in this article are included in the article, s 9.• Elsharkawy H, El-Boghdadly K, Kolli S, Esa WA, DeGrande S, Creative Commons licence, unless indicated otherwise in a credit line to Soliman LM, et al. Injectate spread following anterior sub-costal , the material. If material is not included in the article s Creative Commons and posterior approaches to the quadratus lumborum block. Eur J licence and your intended use is not permitted by statutory regulation or Anaesthesiol. 2017;34:587–95 A comparative cadaveric study exceeds the permitted use, you will need to obtain permission directly demonstrating the injectate spread following posterior and an- from the copyright holder. To view a copy of this licence, visit terior quadratus lumborum blocks. This study demonstrated http://creativecommons.org/licenses/by/4.0/. various nerves and thoracolumbar fascia involved with poste- rior and anterior QL blocks. 10. Willard FH, Vleeming A, Schuenke MD, Danneels L, Schleip R. The thoracolumbar fascia: anatomy, function and clinical consider- References ations. J Anat. 2012;221:507–36. 11. Saito T, Den S, Tanuma K, Tanuma Y, Carney E, Carlsson C. Anatomical bases for paravertebral anesthetic block: fluid commu- Papers of particular interest, published recently, have been nication between the thoracic and lumbar paravertebral regions. highlighted as: Surg Radiol Anat. 1999;21:359–63. • Of importance 12. Karmakar MK, Gin T, Ho AM. Ipsilateral thoraco-lumbar anaes- •• thesia and paravertebral spread after low thoracic paravertebral in- Of major importance jection. Br J Anaesth. 2001;87:312–6. 13. Klaassen Z, Marshall E, Tubbs RS, Louis RG Jr, Wartmann CT, 1. Blanco R, Ansari T, Girgis E. Quadratus lumborum block for post- Loukas M. Anatomy of the ilioinguinal and iliohypogastric nerves operative pain after caesarean section: a randomised controlled trial. with observations of their spinal nerve contributions. Clin Anat. Eur J Anaesthesiol. 2015;32:812–8. 2011;24:454–61. 2.• Krohg A, Ullensvang K, Rosseland LA, Langesæter E, Sauter AR. 14. La Colla L, Ben-David B, Merman R. Quadratus lumborum block The analgesic effect of ultrasound-guided quadratus lumborum as an alternative to lumbar plexus block for hip surgery: a report of 2 block after cesarean delivery: a randomized clinical trial. Anesth cases. A A Case Rep. 2017;8:4–6. – Analg. 2018;126:559 65 RCT showing the analgesic benefit of 15. Spence NZ, Olszynski P, Lehan A, Horn JL, Webb CA. Quadratus – ultrasound guided posterior quadratus lumborum block with lumborum catheters for breast reconstruction requiring transverse ropivacaine versus saline for post cesarean delivery opioid con- rectus abdominis myocutaneous flaps. J Anesth. 2016;30:506–9. sumption and pain intensity scores. 16. Visoiu M, Yakovleva N. Continuous postoperative analgesia via 3. Mieszkowski MM, Mayzner-Zawadzka E, Tuyakov B, quadratus lumborum block: an alternative to transversus abdominis Mieszkowska M, Żukowski M, Waśniewski T, et al. Evaluation plane block. Paediatr Anaesth. 2013;23:959–61. of the effectiveness of the quadratus lumborum block type I using 262 Curr Anesthesiol Rep (2019) 9:257–262

17. Chakraborty A, Goswami J, Patro V.Ultrasound-guided continuous 33. Aksu C, Gürkan Y. Ultrasound guided quadratus lumborum block quadratus lumborum block for postoperative analgesia in a pediatric for postoperative analgesia in pediatric ambulatory inguinal hernia patient. A A Case Rep. 2015;4:34–6. repair. J Clin Anesth. 2018;46:77–8. 18. Ueshima H, Yoshiyama S, Otake H. The ultrasound-guided contin- 34. Carvalho R, Segura E, Loureiro MD, Assunção JP. Quadratus uous transmuscular quadratus lumborum block is an effective anal- lumborum block in chronic pain after abdominal hernia repair: case gesia for total hip arthroplasty. J Clin Anesth. 2016;31:35. report. [Article in Portuguese.]. Rev Bras Anestesiol. 2017;67:107–9. 19. Kadam VR. Ultrasound-guided quadratus lumborum block as a 35. Sá M, Cardoso JM, Reis H, Esteves M, Sampaio J, Gouveia I, et al. postoperative analgesic technique for laparotomy. J Anaesthesiol Quadratus lumborum block: are we aware of its side effects? A Clin Pharmacol. 2013;29:550–2. report of 2 cases. [Article in Portuguese. Rev Bras Anestesiol. 20. Johnston DF, Sondekoppam RV. Continuous quadratus lumborum 2017;68:396–9. block analgesia for total hip arthroplasty revision. J Clin Anesth. 36. Corso RM, Piraccini E, Sorbello M, Bellantonio D, Tedesco M. 2016;35:235–7. Ultrasound-guided transmuscular quadratus lumborum block for 21. Hernandez MA, Vecchione T, Boretsky K. Dermatomal spread fol- perioperative analgesia in open nephrectomy. Minerva Anestesiol. lowing posterior transversus abdominis plane block in pediatric 2017;83:1334–5. patients: our initial experience. Paediatr Anaesth. 2017;27:300–4. 37. Suri A, Sindwani G, Sahu S, Gupta N, Sureka S. Surgeon assisted 22. Sondekoppam RV, Ip V, Johnston DF, Uppal V, Johnson M, quadratus lumborum block: “Gaurav–Aditi” technique case series. Ganapathy S, et al. Ultrasound-guided lateral-medial transmuscular J Clin Anesth. 2017;43:48–9. quadratus lumborum block for analgesia following anterior iliac 38. Ueshima H, Otake H. Clinical experiences of unilateral anterior crest bone graft harvesting: a clinical and anatomical study. Can J sub-costal quadratus lumborum block for a nephrectomy. J Clin Anaesth. 2018;65:178–87. Anesth. 2018;44:120. 23. Dietemann JL, Sick H, Wolfram-Gabel R, Cruz da Silva R, Koritke 39. Sindwani G, Suri A, Shrivastava D, Sureka S. Laparoscopic guided JG, Wackenheim A. Anatomy and computed tomography of the continuous type 1 quadratus lumborum block: Sindwani technique normal lumbosacral plexus. Neuroradiology. 1987;29:58–68. with case series. J Clin Anesth. 2017;42:93–4. 24. Awad IT, Duggan EM. Posterior lumbar plexus block: anatomy, 40. Hockett MM, Hembrador S, Lee A. Continuous quadratus approaches, and techniques. Reg Anesth Pain Med. 2005;30:143–9. lumborum block for postoperative pain in total hip arthroplasty: a 25. Benetazzo L, Bizzego A, De Caro R, Frigo G, Guidolin D, Stecco case report. A A Case Rep. 2016;7:129–31. C. 3D reconstruction of the crural and thoracolumbar fasciae. Surg 41. Ohgoshi Y, Nakayama H, Kubo EN, Izawa H, Kori S, Matsukawa Radiol Anat. 2011;33:855–62. M. Clinical experiences of the continuous quadratus lumborum 26. Arnér S, Lindblom U, Meyerson BA, Molander C. Prolonged relief block via paramedian sagittal oblique approach. J Clin Anesth. of neuralgia after regional anesthetic blocks: a call for further ex- 2017;38:89–90. perimental and systematic clinical studies. Pain. 1990;43:287–97. 42. Green M, Hoffman CR, Iqbal U, Ives OO, Hurd B. Transmuscular 27.•• El-Boghdadly K, Elsharkawy H, Short A, Chin KJ. Quadratus quadratus lumborum block reduced length of stay in patients receiv- lumborum block nomenclature and anatomical considerations. ing total hip arthroplasty. Anesth Pain Med. 2018;8(6):e80233. RegAnesthPainMed.2016;41:548–9 Letter to the editor de- 43. Ueshima H, Otake H. Lower limb amputations performed with scribing the Quadratus lumborum block nomenclature based anterior quadratus lumborum block and sciatic nerve block. J Clin on the anatomical considerations. This describes the lateral QL, Anesth. 2017;37:145. posterior QL and anterior QL blocks along with various 44. Segura-Grau E, Magalhães J, Cabral F, Costa C. Continuous thoracolumbar fascia. quadratus lumborum type 2 block: good analgesia alternative for 28.• Carline L, McLeod GA, Lamb C. A cadaver study comparing complex iliac and acetabulum fracture. J Clin Anesth. 2018;46:91. spread of dye and nerve involvement after three different quadratus 45. Watanabe K, Mitsuda S, Tokumine J, Lefor AK, Moriyama K, lumborum blocks. Br J Anaesth. 2016;117:387–94 A cadaver Yorozu T. Quadratus lumborum block for femoral-femoral bypass study comparing the dye spread following QL1, QL2 and graft placement: a case report. Medicine (Baltimore). 2016;95:e4437. Transmuscular QL blocks. This cadaver study demonstrates 46. Iwamitsu R, Ueshima H, Otake H. Intermittent bilateral posterior the muscles and nerves involved with 3 different types of QL quadratus lumborum block was effective for pain management in blocks using the old nomenclature. lumbar spinal fusion. J Clin Anesth. 2017;42:16. 29.•• Dam M, Hansen CK, Børglum J, Chan V, Bendtsen TF. A trans- 47. Ueshima H, Hiroshi O. Incidence of lower-extremity muscle weak- verse oblique approach to the transmuscular quadratus lumborum ness after quadratus lumborum block. J Clin Anesth. 2018;44:104. block. Anaesthesia. 2016;71:603–4 A technical description of 48. Wikner M. Unexpected motor weakness following quadratus Transmuscular quadratus lumborum block and the lumborum block for gynaecological laparoscopy. Anaesthesia. – Shamrock sign. 2017;72:230 2. 30. Elsharkawy H. Quadratus lumborum block with paramedian sagit- 49. Gitman M, Barrington MJ. Local anesthetic systemic toxicity: a tal oblique (subcostal) approach. Anaesthesia. 2016;71:241–2. review of recent case reports and registries. Reg Anesth Pain – 31. Ishio J, Komasawa N, Kido H, Minami T. Evaluation of ultrasound- Med. 2018;43:124 30. guided posterior quadratus lumborum block for postoperative anal- gesia after laparoscopic gynecologic surgery. J Clin Anesth. 2017;41:1–4. 32. Shaaban, M, Esa, WA, Maheshwari, K, Elsharkawy, H, Soliman, LM Bilateral continuous quadratus lumborum block for acute post- operative abdominal pain as a rescue after opioid-induced respira- Publisher’sNote Springer Nature remains neutral with regard to jurisdic- tory depression. A A Case Rep. 2015 Oct 1;5(7):107-11. tional claims in published maps and institutional affiliations.